An important concern in rock mechanics is non-homogeneity as joints or fault. This noticeable feature of failures in rock is

appearance of slip surfaces or shear bands, the characteristics of that are associated with deformation being concentrated in a

narrow zones and the surrounding material remaining intact. Adopting the joints as fractures, fractures are well known for their

effects on the mechanical and transport properties of rock. A damaged pro-elasticity multi-plane based model has been developed

and presented to predict rock behavior. In this multi-plane model, the stress–strain behavior of a material is obtained by

integrating the mechanical response of an infinite number of predefined oriented planes passing through a material point.

Essential features such as the pro-elasticity hypothesis and multi-plane model are discussed. The methodology to be discussed

here is modeling of slip on the local and global levels due to the deformation procedure of the existing/probable joints of rock and

this method has a potential of using different parameters on different sampling planes to predict inherent anisotropy of rocks.

Upon the presented methodology, more attention has been given to slip initiation and propagation through these joints. In

particular, softening in non-linear behavior of joints in going from the peak to residual strengths imparts a behavior often

associated with progressive failure. The predictions of the derived stress–strain model are compared to experimental results for

marble, sandstone, Quartz mica schist and anisotropic schist. The comparisons demonstrate the capability of this model to

reproduce accurately the mechanical behavior of rocks.